WASTE LOADINGS FROM A FRESHWATER ATLANTIC SALMON FARM IN SCOTLAND1

ABSTRACT: Recent studies suggest that waste generation from the freshwater phase of Atlantic salmon (Salmo salar L.) production varies considerably on an annual basis. A fish farm on the West Coast of Scotland was visited regularly during a two-year period to determine inflow and outflow water quality. Waste output budgets of suspended solids (SS), biochemical oxygen demand (BOD), total nitrogen (TN), total phosphorus (TP), total ammonia nitrogen (TAN = NH₃+NH₄⁺), dissolved reactive phosphorus (DRP) and total phosphorus (TP) were produced. The annual waste loadings obtained were 71 kg TN t fish^?1 yr^?1 (one year of data only), 10.9–11.1 kg TP t fish^?1 yr^?1, 1.2–2.1 kg DRP t fish^?1 yr^?1, 422–485 kg BOD₅ t fish^?1 yr^?1, 327–337 kg SS t fish^?1 yr^?1, and 30–35 kg TAN-N t fish^?1 yr^?1. Simple linear regression models relating waste parameter production to water temperature and feeding regime were developed. When compared to existing data for other salmonid production systems, greater ranges of daily waste loadings were observed. Wide variations in concentrations of these parameters during a daily cycle were also observed, suggesting that mass balance estimates of waste production will provide more robust estimates of waste output than frequent monitoring of outflow water quality.     

Starch- polyvinyl alcohol crosslinked film— performance and biodegradation

Starch-PVOH cast films were prepared with and without crosslinking agent (hexamethoxymethylmelamine) in the absence of plasticizer. Moisture absorption in films without crosslinking agent at a low relative humidity was similar to that of PVOH and increased as the relative humidity increased. Films with crosslinking agent showed moisture absorption linearly proportional to the relative humidity. Significant improvement in resistance to water disintegration for crosslinked starch-PVOH films was observed. While the tensile strength decreased with increased relative humidity, crosslinking significantly improved the tensile strength. Increased PVOH content improved elongation of films even when the relative humidity was 80% or higher. Biodegradation studies revealed that the degradation rate was negatively correlated with the PVOH content in films and crosslinking generated more converged degradation curves. Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable.     

平衡调温调湿方式中变流量冷冻水系统设计

通过对变流量冷冻水系统的分析指出，在运用平衡调温调湿方式的空调系统中，应用变流量冷冻水系统可以较大地节约能源和投资；并提出了实现这种应用的方法。     

On the response of 500 gal propane tanks to a 25% engulfing fire

This paper presents detailed data on the thermal response of two 500 gal ASME code propane tanks that were 25% engulfed in a hydrocarbon fire. These tests were done as part of an overall test programme to study thermal protection systems for propane-filled railway tank-cars.

The fire was generated using an array of 25 liquid propane-fuelled burners. This provided a luminous fire that engulfed 25% of the tank surface on one side. The intent of these tests was to model a severe partially engulfing fire situation.

The paper presents data on the tank wall and lading temperatures and tank internal pressure. In the first test the wind reduced the fire heating and resulted in a late failure of the tank at 46 min. This tank failed catastrophically with a powerful boiling liquid expanding vapour explosion (BLEVE). In the other test, the fire heating was very severe and steady and this tank failed very quickly in 8 min as a finite rupture with massive two-phase jet release. The reasons for these different outcomes are discussed. The different failures provide a range of realistic outcomes for the subject tank and fire condition.     

Study of Pollution of the Plitvice Lakes by Water and Sediment Analyses

The process of eutrophication in form of intense plant growth has been observed in some lakes and water streams at the Plitvice Lakes National Park in central Croatia. Here we investigate whether this phenomenon is a consequence of anthropogenic pollution or due to naturally produced organic matter in the lakes. We applied chemical analysis of water at two springs and four lakes (nutrients, dissolved organic carbon (DOC), trace elements) and measurements of surface lake sediments (mineral and organic fraction analyses, trace elements) in four different lakes/five sites. The chemical composition of water does not indicate recent anthropogenic pollution of water because the concentrations of most trace elements are below detection limits. The concentrations of DOC and nutrients are slightly higher in the area of increased eutrophication-plant growth. Also the content of organic matter in the sediment is at the highest level in areas with highest C/N ratio indicating that the organic fraction of this sediment is mainly of terrestrial origin. There is no significant difference among the trace element concentration in the upper segment of all cores, deposited approximately during last 50 years when higher anthropogenic influence is expected due to development and touristic activity, and the lower part of the cores, corresponding to the period approximately 100–200 years before present. The content of trace elements and organic matter in sediments decreases from the uppermost lake downstream. According to our results there is no indication of recent anthropogenic pollution in water and sediment. Higher concentrations of DOC in water as well as phosphorus and some other elements in the lake sediment can be a consequence of input of natural organic matter to the lake water.     

马头电厂废水处理系统介绍

介绍了河北马头电厂废水处理工艺系统流程、设计及系统调试运行指标。处理后的电厂废水作为循环冷却水的补水,减少了新鲜水用量和污水排放量，对北方地区厂区废水回收利用具有借鉴意义，在火电厂废水资源利用方面有很好的应用前景。     

河津发电厂废水零排放实施及建议

介绍了河津发电厂目前的用水、排水情况及工业废水零排放实施方案，对方案实施后的效果进行了预测，同时对废水零排放实施后运行中可能出现的问题进行了分析并提出了建议。     

仪化热电厂提高循环水浓缩倍率的措施

针对仪化热电厂将循环水用作冲灰水，导致浓缩倍率只有1.6，以及凝汽器铜管腐蚀结垢严重等问题，提出了隔断循环水与冲灰水的直接联系，实现闲路循环，对凝汽器铜管进行酸洗，并对循环水实施加缓蚀阻垢荆、杀菌剂和旁流过滤等办法，全部实施后产生了很好的效益，值得借鉴。     

二级处理后的城市污水用作电厂冷却水若干问题的探讨

介绍了二级处理后的城市污水（TSE）用作电厂开式循环冷却水时，由于城市污水中氨氮、微生物及菌类含量较高，可能给循环水系统带来的危害，并探讨了危害产生的原因及控制措施。     

城市中水回用于循环冷却水的氨氮去除试验研究

对氨氮浓度较高的城市中水回用于循环冷却水进行了静态和动态模拟试验，研究了氨氮在两种不同试验条件下的变化以及对系统产生的影响。试验结果表明：随着浓缩倍率的升高，循环水中氨氮浓度大幅度下降，大部分氨氮是由于冷却塔对氨的吹脱作用而被去除。试验过程中，氨氮浓度的降低没有导致系统的腐蚀。用氨氮浓度较高的城市中水回用于循环冷却水是可行的。